benjishults

class Base {
  public void foo(Base x) {
    System.out.println("Base.Base");
  }
  public void foo(Derived x) {
    System.out.println("Base.Derived");
  }
  public void bar(Object x) {
    System.out.println("bar-Base:Object");
  }

benjishults

public class AuditService {
  private static final Logger LOGGER = LoggerFactory.getLogger(AuditService.class);
  private AuditPublishingService auditPublishingService;
  public AuditService(AuditPublishingService auditPublishingService) {
    this.auditPublishingService = auditPublishingService;
  }
  public void auditDownload(Task taskObj) {
    DocAccessAuditRequest request = publishDocAccessEvent(taskObj, DocAccessType.DOWNLOAD);
    LOGGER.info("Audit log for Download :DocAccessAuditRequest", request);
  }

benjishults

public interface ExternalGroupHelper {
  boolean isMember(User u, String extGroupId);
  List<Member> members(String extGroupId);
}

benjishults

public class ExternalGroupHelperProvider implements ContextAware {
  // ... save the application context in a field named context ...
  public ExternalGroupHelper getHelperForType(String groupType) {
    return context.getBeanByName(groupType + "ExternalGroupHelper");
  }
}

benjishults

  CommentUserGroup cug = cugDao.find(commentUserGroupId);
  ExternalGroupHelper groupHelper = extGroupHelperProvider.getHelperForType(cug.getExtGroupType());
  if (groupHelper.isMember(securityContextHelper.getCurrentUser(), cug.getExtGroupId())) {
    return groupHelper.members(cug.getExtGroupId());
  } else {
    return Collections.emptyList();
  }

benjishults

{
  id: "<guid>",
  extGroupType: "<code-name for group type>",
  extGroupId: "<FK into a table determined by the group type>"
}

benjishults

{
  commentUserGroupId: "<ID from the C_U_G table>",
  author: "<user id>",
  payload: "<comment content>"
}

benjishults

public class Comment {
  private String commentUserGroupId;
  private User author;
  private Object payload;
  // ... constructor, getters, equals, hashCode ...
}

benjishults

public interface CommentAddedListener {
  void processComment(Comment comment);
}

benjishults

public class CommentController {
  private static final Logger LOG = LoggerFactory.getLogger(CommentController.class);

  // implementation of listeners might need to be thread safe
  // depending on whether you allow dynamic change to
  // listener registration
  private Set<CommentAddedListener> listeners;

  // ... some fields and constructor omitted ...